Call a function with a specified number of leading arguments forced before the call if the function is a closure.
forceAndCall(n, FUN, ...)number of leading arguments to force.
function to call.
arguments to FUN.
forceAndCall calls the function FUN with arguments
  specified in ….  If the value of FUN is a closure
  then the first n arguments to the function are evaluated
  (i.e. their delayed evaluation promises are forced) before executing
  the function body.  If the value of FUN is a primitive then
  the call FUN(…) is evaluated in the usual way.
forceAndCall is intended to help defining higher order
  functions like apply to behave more reasonably when the
  result returned by the function applied is a closure that captured its
  arguments.